Tagged Questions

A chosen-ciphertext attack (CCA) is an attack model for cryptanalysis in which the cryptanalyst gathers information, at least in part, by choosing a ciphertext and obtaining its decryption under an unknown key.

I've studied that the Bleichenbacher's CCA attack on PKCS#1 v1.5. is a base to many versions of attacks in the area.
I'm trying to understand that attack, but every explanation I saw starts with the ...

This is an exam question an i have no idea how to recover the message m.
John wants to send an encrypted message to mary who has a pair of RSA keys, However, John does not know Mary's public key and ...

Is it possible to modify a homomorphic encryption scheme so that it can be CCA2 secure?
From the definition of a homomorphic scheme, it seems that it is malleable, which would result in lack of CCA2 ...

There are many schemes that can advertise themselves with certain security notions, usually IND-CPA or IND-CCA2, for example plain ElGamal has IND-CPA security but doesn't provide IND-CCA security.
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Do you mind if you give me any hints, links or ideas about how to improve the security of double regular encryption and decryption, by using CPA game and CCA game, it sounds interesting question, and ...